Not Applicable.
Not Applicable.
The present invention relates to medical devices, and more particularly to an implantable structure for promoting fusion of adjacent vertebral bodies.
Advancing age, as well as injury, can lead to changes in the bones, disks, joints, and ligaments of the spine producing pain from nerve root compression. Under certain circumstances, alleviation of pain can be provided by performing a spinal fusion. This is a procedure that involves joining two or more adjacent vertebrae so that they no longer are able to move relative to each other.
Many prosthetic devices are known for promoting fusion of the spinal vertebrae, and the devices can be classified, in part, based upon the approach to the spine that will be taken by the surgeon (anterior, posterior, lateral, etc.). None of the known devices is completely satisfactory, and improvements are desirable.
The present invention improves upon known spinal fusion devices, especially those devices intended for an anterior approach to the spine. In an exemplary embodiment, a spinal fixation assembly includes a fusion cage to which a plate is mated. The plate is configured to receive, retain and orient bone screws, thereby holding the fusion cage and adjacent vertebral bodies in a stable relationship to promote fusion.
Additional features of the assembly can include a plate mated to the fusion cage so as to be slidable therewith, and joining them with a mortise and a tenon. The plate can include extensions or tabs through which bone screws are passed and retained on one or both of the superior and inferior sides of the fusion cage. The tabs can be angled to orient the screws as desired.
The fusion cage can include convex superior and inferior surfaces, and it can be tapered from the anterior face to the posterior face. Both the fusion cage and the plate can include insertion tool guide and engagement features, such as bores and notches. Fins can be provided at one or more points on the inferior and superior faces of the fusion cage.